a) Field of the Disclosure
The object of this disclosure relates to the field of methods to repair or strengthen pipe, pipe fittings, and related structures. In one form, the disclosure relates to repairing of thermoplastic pipe and thermoplastic fittings.
b) Background Art
Prior solutions to repairing of pipes, pipe fittings, including thermoplastic pipes and similar structures containing fluid under pressure often require removal of a section of the damaged pipe, or a bypass around the damaged section. In repairs to polyethylene pipe in particular, it has been shown that the adhesives commonly used for repairing of structures such as pipes will not sufficiently adhere to the surface of these thermoplastic, PE, MDPE, and HDPE pipes. As these pipes are often used to transport hydrocarbons, and other fluids including fuel, water, and sewage underground, failures in the pipes and fittings cause substantial concern. In metal pipes, the welding of patches forms heat stressed regions which can be prone to failure.
Current repairs and bypasses are extremely expensive, time-consuming, often unsafe, may result in unnecessary environmental damage, and often do not solve the original problem. As there are approximately 80-thousand miles of thermoplastic pipe being installed every year, this problem must be addressed soon or we will eventually have a very drastic environmental and societal problem.
In the art of existing repair methods of repairing steel pipes, several problems exist. One problem is that when a hole or substantially weakened portion of the pipe is created there is no effective, quick, cheap, safe, environmentally friendly and substantially permanent way of repairing these damaged portions.
In the art of floating covers and similar structures in storage tanks and equivalent structures, flexing and movement of the floating cover often causes stress fractures and larger cracks in the surface of the cover. Current methods to repair these floating lids have proven insufficient.
In the art of thermoplastic pipes, it is often desired to put a fitting on the pipe. For example, to provide a constant supply of the material transported by the pipe to a remote location, such as a residential home. Such a fitting is disclosed in U.S. Pat. No. 4,894,521 incorporated herein by reference. These saddle-type fittings and similar structures have proven to fail over time as the inner surface of the fitting becomes disconnected from the outer surface of the pipe forming a gap through which fluids can escape. Recently, a T-fitting failed, leaking explosive gases into a nearby residential home, which then exploded. The explosion killed at least one occupant. Regarding the compression style fittings, currently, in the state of Texas alone, there are 200,000 estimated failures of these compression style fittings in gas supply lines. These compromised fittings cause substantial problems to the supply of gases and other fluids, as well as environmental and safety concerns. Understandably, a means for repairing these fittings quickly, cheaply and easily is very much desired.
In the art of compression fittings, flexing and movement of the pipe results in a disassociation of the inner surface of the compression fitting from the outer surface of the pipe. This movement can cause leakage, which there is no repair to at this time. One example of such a fitting is the steel compression fitting, as disclosed in U.S. Pat. No. 4,603,893 although many variations of these fittings are utilized. These types of fittings are used to couple two ends of thermoplastic or other pipe.